Superconducting wire made of niobium alloys can be produced by encapsulating preformed fine particles of the alloy in tubes of a ductile metal, such as copper, and then drawing the filled tubes to the desired wire diameter. This procedure is used because these alloys are so brittle that they cannot be drawn directly into wire.
For example, the superconducting niobium alloy Nb.sub.3 Sn can be formed into wire using that procedure. This alloy can be prepared in fine particle form by reacting niobium trichloride and stannous chloride molten sodium metal according to the following reaction: EQU 3NbCl.sub.3 +SnCl.sub.2 +11Na.fwdarw.Nb.sub.3 Sn+11NaCl
A related superconducting alloy, Nb.sub.3 Al, is superior to Nb.sub.3 Sn for some applications, and can also be drawn into wire in the same manner. However, Nb.sub.3 Al cannot be easily formed by reacting niobium and aluminum chloride in molten sodium.